kgg

Remember the Juki LS-1341is only rated for V138 top and in the bobbin. Try V207 on top and V138 in the bobbin and see if that works. Also you may want to get a new Juki throat plate to try. It shouldn't be that expensive. kgg

I have attached a manual for the LS-1341 that may help with the "Lateral position of the feed dog" page 4 and page 7 for the "Needle -to - hook timing". kgg Juki LS-1340&42 Servcie Manual.pdf

I think the bottom tension is to light. A couple of questions: i) what machine are you using? ii) are you doing a drop test on the bobbin to set the bobbin tension? Bobbin Drop Test: With the bobbin in the bobbin case and the end threaded through the tension spring and rested in the palm of left your hand grab the end of the bobbin thread with your right You should be able to raise the bobbin case off your hand about an inch without unwinding. Giving the thread a quick jerk the thread should unwind slightly. A good little video: (https://www.youtube.com/watch?v=lVQWKXZVzu0 iii) are you sewing in pre punched holes? iv) is the machine threaded properly? A couple of photo's of how you have the machine threaded from the thread spool to the needle may help. kgg

I have owned a Reliable Barricade, presently own a Kobe LSZ-1 (which is the same as the Barracuda but less pricey) and have used a Sailrite LSZ-1. My take on the portable walking foot sewing machines. i) Designed for sewing sail cloth while at sea using V92 thread. ii) As the thickness of material being sewn increases the number of stitches per inch increases. iii) The older Sailrite's if I'm not mistaken were made in Taiwan and the newer ones are now made in China. iv) The Sailrite's fit, finish and internal parts are of better quality. v) They come with a real manual written in English with actual photo's, and they have good customer service with a lot of video's covering topics from sewing to repairs. vi) The knockoffs are more to the style of the older Sailrites with little to no support, manuals are less then, typically the two small holes in the bed for mounting attachments like binders are NOT tapped, missing screws, miss aligned presser feet and a top cover that is made of pot metal. The quality well it can be lets say less then. vii) The cost difference for the Sailrite can be hard to justify when you compare the knockoffs at around $500. The difference does buy a lot of replacement parts even buying them from Sailrite. But you have to be prepared to do a lot of going over the machine. My latest knockoff a KOBE LSZ-1 is a table mounted machine that mostly does one particular task, binding. So far it has done about 1200 ft of 0.52mm thick polypropylene binding plus a couple of other things. When I got the machine I gave it a Synthetic oil flush and bath to get rid of metal filings and get oil into the bearings / guides. The height of the presser feet were too low for my needs so I increased the height. I did get the height clearance under the outer and inner presser feet up to 10mm (touch over 3/8") with a few fancy words of encouragement and tinkering. I figure with another adjustment I could probably get at least the outer up to 1/2 inch but that would be useless if I can't get the inner to rise that far which may involve readjusting the top tension release mechanism. Prior to the adjustments the stitches were 8.5 per inch on a 7mm thickness which is a touch over a 1/4" of material which I think is way too many stitches and now it gets 5 per inch on 7mm thick material. On a normal couple layers of cotton fabric it will do 3.5 stitches per inch. I figure this isn't to bad on a Chinese knockoff machine rated at sewing less then 1/4 inch. Other then my own modifications like a drop down roller guide and stitch length indicator the machine has only needed a couple of minor adjustments and a new $10 bobbin case holder as the lever spring has just failed. For my needs I just wouldn't be able to justify the price for a new Sailrite LSZ-1. kgg

The seller of the machine in your Amazon link says it can handle size #16 to #18 needles. This means it could handle V69 (max thread size for most domestic sewing machines) and maybe V92 (smallest thread size for most industrial sewing machines) depending on the thickness and how tough or sticky the material is. Can it handle larger size thread like a Singer 29K 72, I don't know.... If it was a true clone of the Singer 29K 72 it would be able to handle needles from size #9 to #25 needles. This means it could handle threads up to about V138. These machines were designed to do small, short run repairs on items hence the name patcher. A good chart for selecting the correct needle size for the thread size can be found at: ( https://www.tolindsewmach.com/thread-chart.html ) kgg

The Ikonix KS-5618 is the same as the Yamata FY5618 and both are made by a Chinese company called China Feiyue who also make the portable walking foot sewing machines label Family Sew. The 5618 to me seems to be some clone variant on the Juki 563. kgg

Thank you. I downloaded it and had a brief look. I will give it a read later today but it looks like some nice info there. kgg

Close. In some cases it is easier on the cylinder bed machine. With large heavy table top attachments you are probably going to have to attach it to the existing table so leave some clearance around the cylinder arm since the sewing machine has some natural movement / vibrations during sewing. kgg

That is an excellent idea. Take along a sample of what you want to sew and if you can afford it buy a brand name machine rather then a clone. Buy Once, Cry Once kgg

Based on what you have listed and looking at your website. i) post bed (Techsew 830 and the Consew 710 UX ) ii) 1341 class cylinder bed Cobra 26 and Techsew 2750 iii) 441 class cylinder bed Cowboy 3200 I think from a versatility point of view I would go with a 1341 class machine. So you would be looking for either a used Juki LS-341 or clone or new Juki LS-1341 or it's clones. The ideal thing would be to go to a dealer and test a couple of machines with your items and then select the best machine. Keep in mind no one machine will do everything each will have their pro's and cons. kgg

Very Nice. kgg

If possible add a couple photo's of your thread path from the thread spool to the eye of the needle. kgg

Yes. Every time you change thread spools, manufacturers of thread, thread size, needle size change or even changing the color of thread from a white to black (black is stiffer) you need to recheck the bobbin tension. Cheap Chinese thread in my experience is usually of poor quality. I have even had a needle break because of poor quality thread that I using in a pinch. They ran out of thread part way through spooling the cone so they they just joined the two end by tieing a knot to finish the spool. The needle broke when the knot wouldn't go through the eye. To much bobbin tension and you wind up not having the bobbin thread being pulled up into the leather while to little tension and the bobbin thread will be on the top side of the leather. The needle is also important factor as too small a needle for the thread size there isn't enough room for the threads, top and bobbin, to exist in the needle hole and you can get skipped stitches. While to large a needle and the stitch will be sloppy at best. Getting the top and bobbin thread tension right is like two teams having a tug of war with the needle being in the middle. What machine are you using? kgg

From the Purdue University kgg

A good thread size to needle size can be found at ( https://www.tolindsewmach.com/thread-chart.html ). For V138 you need a # 22 in thin and either a #23 or #24 in thicker / tougher leather. The #20 will not provide the correct size hole to allow the thread to move through it properly. That will cause tension problems and slipped stitches. Also are you doing a drop test on the bobbin to get the bobbin tension close? kgg

Great education machine. Doesn't this defeat the purpose of using a machine if you are going to pre-punch the stitching holes? kgg

What size of thread are you using with what needle size? Usually I back stitch about four or five. kgg

To get some answers you need to provide some more information. What and how thick of material are you trying to sew? What size of needle and size of thread are you using? A couple of photo's how you thread the machine from the thread spool to the needle could also be very helpful? kgg

The 3 layers of 6 oz leather or 18 oz in total ( just over 1/4 " thick) with V138 thread should be able to be handled by almost all of the upholstery class flatbed machines like your Juki DNU-1541S and clones but most load the bobbin from underneath the machine. To get the top bobbin loading you need to go up to a Juki LU-1508 class machine or clone. The Juki LU-1508 machine also has a larger bed and a double tensioner and is an overall heavier duty machine. Another option would be to go with a upholstery class cylinder bed machine in the Juki LS-341 or LS-1341 (newer version) or clone where the bobbin is loaded from the top and a flat bed attachment. My opinion of needle flexing is it has a lot to do with the needle size selected for the thread size, the presser foot on the machine and the thickness / toughness of the project. A lot of times it usually be solved by going up a needle and at a slower speed to give better control of the project to prevent side to side movement. The speed of the machine with a servo motor still maybe to much and the machine can be further slowed down by installing a speed reducer pulley. What machines are you looking at (new or used) and what is your budget? kgg

Tell the seller the serial number is typically located on the bed directly below the Singer badge and adjacent to the pillar. A good video on locating the serial number on Singer machines: "Dating your vintage Singer sewing machine" kgg

The machine in the video is a Mitsubishi Du-115 which shows the markings on the handwheel to be 0 to 7 for the stitch length. In the video there is a larger distance between the 6 mark and the 7 mark I am wondering if yours had another handwheel installed at some point in it's life or the markings for 6 and 7 are worn off . kgg

I wouldn't hesitate. Those bases alone are worth that price and are hard to come. kgg

Which one, I missed that. kgg

Looks good. Another good place to check for needles and thread is Wawak.com. Example: i) Needles: ( https://www.wawak.com/sewing/needles/industrial-machine/schmetz-leather-industrial-machine-needles-135x16-tri-dpx16-d-10pack/#sku=smnl135118 ) ii) V92 Thread: ( https://www.wawak.com/thread/thread-by-brand/ae/ae-anefil-thread-tex-90-1100-yds/#sku=thd290be ) kgg

To help with this you could fashion up a edge guide mounted to a little table surface. Don't use a magnetic edge guide on the nose area as it will lift the bobbin up and fowl the bobbin stitches. kgg